Explosive marking and printing apparatus



Feb. 1, 1966 P. A. STOWELL EXPLOSIVE MARKING AND PRINTING APPARATUSFiled June 28, 1963 OXYGEN SUPPLY 9 HYDROGEN SUPPLY PHILIP A, STOWELL o5 0 EL 00 0O) GF 0 EL EL 0 E 6 0 V EL A CL V N 7 Dn T. G G 0 U [L P H GJ [L N I EL 4 P R E LU s 0 0 V 0 H H M N U DI I H m A l 1.. WW CL P W 0I ST U V HDI MW rr. EL I P o E w Aw Wm Nm U Z 0 P f K N 0 0 R M H m R GEL [L m GR DH N R NE EO N NG R A G B R CL [L D G mm m 1 o r R I 2 1 7Q wM A v 5 United States Patent 3,232,221 EXPLOSKVE MARKZNG AND PRENTHJGAPPARATUS Philip A. Stowell, Paoli, Fa, assignor to BurroughsCorporation, Detroit, Mich, a corporation of Michigan Filed June 28,1963, Ser. No. 291,411 6 Claims. (Cl. 101-93) This invention relates tomarking and printing apparatus and more particularly, to a high speedmarking-printing device utilizing the pressure of a wave generated bythe explosion of unstable material in a cavity by an electricalsparkeifeotive to cause an element to mark or print on a record medium.

Heretofore high speed marking and printing devices have: been employedincomputer systems utilizing the pressure of the shock wave generated in asmall cavity by an electrical spark discharge. The work of Early and Orras-described in their patent, U.S. 2,737,882, entitled High. SpeedPrinting and Perforating Machine, and assigned tothe same assignee asthe present invention, indicate the energies required for perforatingand embossing of characters in paper tape. The nature of the sparkdischarge in such devices is such as to produce extremely hightemperatureshock waves of high peak pressures. It has been founddifficult however, to efliciently harness such high temperatures andpressures since much of the heat produced is lost by radiation andabsorption in the walls of the cavity, and much of the pressure is lostby gas leakage in a direction parallel to the record medium.

It is an object of this invention therefore to provide an improvedmarking apparatus which avoids one. or more disadvantages of the priorart arrangements and which has improved operating-efiiciency.

It is a further object of this invention to provide in a printing devicea movable member which is accelenated by means of the pressureexplosively produced in the device.

In accordance with a preferred form of the invention there is provided amember having an explosion chamber in theform of a cylinder, andcontaining at one end thereof a piston which is normally restrainedagainst the open end of the cylinder by springs. The fuel for the devicewhich may be in the form of an explosive mixture of'gases such ashydrogen and oxygen, is admitted to the cylinder by suitable. portsopening thereinto. A type Wheel carrying raised type is spaced from thepiston in a manner'to permit passage of a record medium and ribbonthcrebetween. When a selected character on the type wheel is initscorrect position behind the paper to be printed upon, the explosivecharge in the cylinder is detonated: The explosion occurring in thecylinder drives thepiston outwardly until it is arrested by impactingagainst the record medium to cause the latter to be driven against theribbon and the raised hard type face forming an' impression of theselected character upon the record medium.

For a better understanding of the present invention together with otherand further objects thereof, reference is hadto the. followingdescription taken in connection with the accompanying drawings and itsscope will be pointed out-inthe appended claims. In the drawings:

FIG.- 1 is a schematic view partially in section showing thevariousparts of the printing device;

FIG. 2 is a sectional view taken along the li-ne-2'-2 of FIG. 1showingorifices leading into the piston chamber;

FIG. 3 is a partial view of a modified form of the invention.

Referring to FIG. 1 of the drawing there is shown a two-part housing 12comprising a base portion 13 and a head portion 14, which when joinedtogether form an explosion chamber in the form of the cylinder 15. Apiston 16 is slidably received in'theforwardend of the cylinder and isrestrained as by springs 17. The fuel for the explosion in the cylindermaybe a hydrogen-oxygen mixture, which gases are admitted from ahydrogen supply 18, and an oxygen supply 19. The gases, separatelyadmitted to the cylinder 15 by means of ports or orifices 2t and 21formed within the base member 13, maybe detonated by a spark dischargedevice 23 which is inthe form of a coaxial spark plug. A typewheel 25having a font of raised type characters 26 about its periphery, isspaced from the free'end of the piston lose as to provide a guide, gapor passage for a recordmedium 27 and a marking ribbon 28. The type wheelis normally rotated at high speed, by means not shown, so that when thede sired character is in line with the piston 16, the explosive chargewithin the cylinder 15 is detonated. The resulting explosiondrives thepiston 16 at a high rate of speed forwardly toward the type wheel untilit is arrested by impacting against the record medium 27' on whichprinting is to occur. The ribbon 28'disposed behind the record mediumand in front of the type wheel 25, causes the desired mark to be madewhen the record medium and ribbon are thus driven against the raisedhard type face'26.

Considering the housing 12 in greater detail it is seen that the basemember 13 includes a circumferentially out.

or grooved portion 3t defining a portion of a hydrogen inlet manifold,see FIG. 2, and a like formed circumferential groove 3.1 is provided toconstitute a portion of an oxygen inlet manifold. In each case thegrooves 30 and.

31 are less than a semi-circle in their circumferential extent and areseparated from each other by the solid or ungrooved portions 32 and 33,as seen in FIG. 2. The rear portion of cylinder 15 in base member 13 isthreaded at 34 to receive thumbscrew 35 whereby the chamber volume ofthe cell may be varied to obtain a fine adjustment relative to theenergy content of the explosion. The forward end 36 of the base memberis of a reduced diameter corresponding with the inner diameters of thegrooves 3 3, 31 and is drilled radially toform the aforementionedorifices Ztl and 21. The head. member 14 is recessed as at 37, andincludes a dimension which corresponds to the outer diameters of groovesPill, 31. The outward face 38 of the reduced portion 3.5 of base member13, bottoms on the face 39 of recess 37 to thereby form a hydrogen inletmanifold 40 with groove 30 and an oxygen inlet manifold 41 with groove31. Bolts 42 secure the base 13 and head 14 together in the mannershown.

Piston 16 is formed to include an elongated skirt 43 which rides withincylinder 15 and is effective when in its nonaprint position, to seal theexhaust ports 44- formed in the head member 14. As the piston advancesas a result of the charge in the cell being detonated, the skirt 43uncovers the exhaust ports 44'thus permitting the compressed hot gasesin the cylinder to escape.

The forward end of the piston includes a reduced head portion 4-5 whichserves to push the record medium and ribbon against the type face 26.The piston 16' further includes a radially extending skirt 46 whichextends be yond the reduced or neck portion 4-7 of the head 14.Theaforementioned springs 17 are thus secured at one of their ends tothe outwardly projecting peripheral edge of the skirt 46 and'at theirinner ends to the face 48 of the member 14.

In order to introduce the desired proportions of-hydrogen and oxygeninto the cylinder for an explosion of adequate energy, means areprovided for controlling the flow rates of the two gases separately. Forthis purpose the oxygen supply 19 with conduit 50 leading to. theaforementioned oxygen inlet manifold 41 includes an oxygen regulatorvalve 51 in the conduit. In a similar manner, the hydrogen supplydesignated 18 with conduit 52 leading to hydrogen inlet manifold 40,includes a hydrogen regulator valve 53, and in addition, a normallyclosed solenoid actuated valve 54, to further control the hydrogensupply.

The latter solenoid valve d has been found desirable and is provided forthe following reason: When the cell detonates, incoming gases combine toburn in the cell until cut-off. Thus the unit cannot fire again untilthe flame is extinguished. The flame can be blown out, or put out byshutting off the hydrogen flow. If the oxygen alone is shut off, thehydrogen will continue to burn in the air outside the cell. It ispossible to interrupt both the hydrogen and oxygen supplies but this isnot essential from the standpoint of functionality. The abovementionedtwo-way solenoid actuated valve 54 is therefore included in hydrogenline 52. The solenoid valve includes a housing containing a coil winding55, a plunger 56, apertured as at 57, to permit flow of hydrogen throughconduit 52, and a suitably apertured fitting 53 surrounding conduit 52and receiving plunger 56. When the aperture 57 of plunger 56 is axiallyaligned with conduit 52, as illustrated, the plunger 56 is in its openposition and hydrogen under pressure from supply 18 is fed to thecombustion chamber 15. Upon a print signal being received by theprinting device to fire the spark plug 23-, the plunger 56 of solenoid54 is tie-energized and the spring 59 thereby advances the plunger tothe right to momentarily cut elf the flow of hydrogen into conduit 52.Thereafter solenoid coil 55 is re-energized to restore the plunger 56 toits open position relative to line 52 and against the action of spring59 so that the cell is once again in its ready state. Due to the factthat oxygen has a greater viscosity than hydrogen it has been foundnecessary to provide as shown in FIG. 2 of the drawings, a greaternumber of oxygen inlet ports or orifices 21 than the number of hydrogeninlet orifices 20. This construction helps to insure that there will notbe an excess of one gas over that of the other in the mixture, relativeto the proportions which are desired.

It has been found desirable prior to firing the cell that the same bepreheated, which preheating is accomplished by the use of an electricalcartridge heater 60 received within an annular recess 61 in the rearwardportion of the base member 13. The heater is shown connected in seriesby means of leads 62, 62a with a thermostat 65, the same being suppliedwith a current from AC. voltage source 63. The thermostat extends withinthe side walls of the base member 13, so that a portion thereof is fiushwith the walls of cylinder 15. When the combustion chamber has beenbrought up to an adequate temperature, the thermostat 65 cuts offadditional current flow to the cartridge heater 60, and permits furthercurrent flow only as may be needed to maintain adequate operatingtemperatures, above the boiling point of water. The use of theabovedescribed heater has been found desirable because the products ofcombustion of hydrogen and oxygen are water. The same may thus condenseon the surfaces which are below boiling point at atmospheric pressure.Hence, it is necessary to insure that piston 16, cylinder 15, coaxialspark plug 23, and all remaining parts in the explosion chamber whichcome in contact with the products of combustion be raised to atemperature sufiicient to assure that such condensation does not occur.

In operation the explosive printing device functions as follows: Adigital character code, for instance representing a desired character,is applied from a source not shown to the buffer and trigger generatorcircuit device 70, which translates this character and determines anecessary time interval which must lapse after receiving a synchronizingpulse from the type wheel in order that the explosion may occur when thedesired type face is in its correct position. After the synchronizingpulse from the type wheel has elapsed, a trigger pulse is applied to thewide range pulse generator 72, which then functions to generate astandard pulse for application to a flip flop circuit device designated74. The pulse simultaneously proceeds to a pulse delay circuit indicatedat 76 and also to a pulse operated relay device designated 78. The flipflop circuit device 74 immediately flips into the ZERO state and remainsthere until a delay pulse from the pulse delay circuit '76 arrives andflips it back into the ONE state. This generates a pulse of standardizedduration which acts as a trigger to the high voltage pulse generatorcircuit device 30. For the duration of the trigger pulse the highvoltage generator device 80 connected to the coaxial spark plug 23 byleads 81, 82 with resistor 83 in lead 81, puts out a pulse of suflicientvoltage to cause a useful spark across the spark plug 23. The source ofthis voltage is a high voltage power supply designated 85.

The simultaneous arrival of the pulse from the wide range pulsegenerator 72 to the pulse operated relay 78, causes the same tointerrupt the hydrogen supply by interrupting the holding current tocoil 55 of solenoid valve 54. The pulse operated relay circuit 78 asshown, includes an inductor coil 79 suitably connected to ground.Application of the pulse from the wide range pulse generator 72 appliesthis pulse across inductor or coil 79. This causes contact 79A ofinductor 79 to open thereby interrupting the current flow from the AC.voltage supply 63. The latter current flow to coil 55 of solenoid 54 isthus interrupted which thereby enables spring 59 encircling solenoidplunger 56 to move the same to the right to thereby block the flow ofhydrogen to the cell which has since been detonated. Thereafter a delaypulse from the pulse delay circuit 76 through inductor coil 79 closescontact 79A to thereby permit current to flow from the A.C. voltagesupply 63. The solenoid coil 55 is thus re-energized and plunger 56 ismoved against the action of spring 59 to its initial open position sothat aperture 57 is aligned with conduit 52 to thereby permit thecombustion chamber to be charged with hydrogen for a subsequent cycle ofoperation.

In accordance with a modified form of the invention as shown in FIG. 3,the head of the piston 43 is shown as including a male die element 85which cooperates with a female die member 87. In the non-print positionof the piston 43, the same is spaced from member 87 to permit passage ofa record member or work-piece 89 which is adapted to be punchedtherebetween. The female die member 87 is apertured as at 90 to receivethe reduced die portion 85, as shown. In all other respects theconstruction of the combustion cylinder may be similar to that describedin FIG. 1 above. Depending on the material to be perforated or punched,as designated by perforations 91 in the material 89, the energy contentof the explosion may be varied by adjusting the chamber volume or" thecombustion device. This may be done by rotation of the thumbscrew 35 asseen in FIG. 1 above.

While there have been described what are at present considered to be thepreferred embodiments of this invention, it will be obvious to thoseskilled in the art, that various changes and modifications may be madeherein without departing from the invention. For example, althoughcylinder gases may be used for fuel and oxygen with this device, it alsois within the purview of this invention that these gases be generated byelectrolysis of water. This would require merely an electrolytic celland an electrical rectifier. It may be further seen that this device mayalso be used if desired, for such other industrial operations asstamping, embossing or as an actuator of a type where very high rates ofacceleration are desired. It should further be apparent that a pluralityof such explosion chambers 15 having movable piston elements '16, may bedisposed in a single line across the page and adapted to cooperate inparallel with a rotata-ble drum having columns of circumferentiallydisposed type therearound to mark or otherwise print out a completelineof characters simultaneously. Alternatively, itis equally within thepurview of this invention to provide a single combustion cell and pistonas illustrated, which may be mounted for movement along a line par-allelto such a drum having type characters therearound and in which onecharacter is printed at a time, with successive characters being printedor marked until a complete line is made.

The principal advantages of thisdevice are the very high rates ofacceleration obtainable in the piston because of the large force whichcan be applied thereto as compared to the force that may be available inelectrically operated solenoids and its low mass compared to the mass ofa solenoid plunger. In addition, very low currents are required toinitiate the explosion in the unstable gases by means of the spark plugand as a consequence there is little erosion of the electrodes. Also, byemploying a piston device to seal the explosion chamber, greatlyimproved efiiciencies are obtained. It is therefore aimed in theappended claims to cover all such changes, modifications, as fall withinthe true spirit and scope of this invention.

What is claimed is:

1. Printing apparatus comprising, a body having an elongated cavity forcontaining an explosive mixture of gases therein, said mixture whenexploded forming a reaction product which condenses at ambienttemperature, heater means received in said body for preheating the bodyto prevent said condensation, a piston member movable within saidcavity, a member juxtaposed to the free end of said piston and inclosely spaced relationship therewith to permit a record medium to beinserted therebetween, separate value and conduit means for introducingand regulating the flow of said gases into said cylinder in accordancewith their viscosities, spark means extending into said cylinder, andcircuit means connected to said heater means and including a source ofpower connected to said spark means for producing an explosion of thegas in said cavity to thereby accelerate the piston which is caused tomark the record medium, venting means associated with said cavity forremoving said reaction product, and thermostat means associated withsaid body and connected with said heater means.

2. Marking apparatus comprising, a body having a cavity in the form of acylinder therein, means for varying the chamber volume of said cavity,separate valve and conduit means for controlling the fiow of hydrogenand a continuous flow of oxygen separately into said cylinder formixture within the latter, said conduit means including means forregulating the flows in accordance with the viscosities of the oxygenand hydrogen, spark discharge means extending within one end of saidcylinder, a piston mounted for movement between mark and non-markpositions within the other end of the cylinder and having a portionprojecting therefrom, a met ber positioned in spaced relation from theprojecting portion of the piston to permit passage of a record mediumtherebetween, circuit means including a source of power connected tosaid electric discharge means and operable for producing an explosion insaid cylinder such that energy is transferred to said piston to causethe same to mark, heater means for preventing condensation of thereaction product of the explosion, exhaust means associated With saidcylinder for removing the reaction product of said explosion, bias meansassociated with said piston and said body for returning said piston toits nonmark position, and means associated with said valve and conduitmeans for the hydrogen and actuated by operation of said circuit meansfor momentarily interrupting the flow of said hydrogen.

3. Printing apparatus comprising, a body having an elongated cylindertherein, a piston mounted for sliding movement in one end of thecylinder for effecting printing on a-recordrnedium, means forseparatelyintroducing.

a plurality. of ga-ses'in-theform of hydrogentand'ioxygenw within thecylinder to formxan explosive mixture therein,- said introducing meansincluding inlet port means having a first volume for introducing thehydrogen into the cylinder and inlet port means havingga secondjvolumewhich is greater than said first volume for introducingtheoXygen intothe cylinder, means for controlling the. flow. of said'gases into thecylinder, a spark device exposedto theinterior of the cy'linder, asurface spaced fromthe piston and in opposedrelationshi-p thereto forpermitting saidrecord medium to be guided therebetween, circuit meansincluding a source of power connected'to said spark device for producinga controlled explosion in the cylinder such that the explosive reactiontransfers energy to the piston to accelerate it and cause it to effectprinting on the record medium, heater means for preventing condensationof the reaction product of the explosion, and venting means for removingthe reaction product from the cylinder.

4. High speed printing apparatus comprising, a body having a cylindertherein, a first valve for controlling the flow of hydrogen into thecylinder, a second valve for controlling a separate continuous flow ofoxygen into the cylinder .to mix with the hydrogen, inlet port meanshaving a first volume for conducting hydrogen coming from the firstvalve into the cylinder, inlet port means having a second volume whichis greater than said first volume for conducting oxygen coming from thesecond valve into the cylinder, spark discharge means exposed to theinterior of the cylinder, a piston slidably mounted in the cylinder formovement between print and non-print positions, said piston having anend portion projecting from the cylinder and a surface on the endportion which seals the cylinder when the piston is in its non-printposition, a plurality of type characters, said type characters and saidbody being relatively movable at high speed to position a characterselected for printing in spaced relation to the projecting portion ofthe piston to permit passage of record means therebetween, circuit meansincluding a source of power connected to the spark discharge means forproducing an explosion in the cylinder such that energy is transferredto the piston causing the piston to move against the record means andthe record means to move against the selected type character, exhaustport means normally closed by the piston and opened by movement thereoffor removal of the by-products of the explosion, means biasing thepiston to its non-print position, means for preventing condensation inthe cylinder, and a third valve under control of said circuit means forinterrupting the flow of hydrogen from said first Valve.

5. High speed printing apparatus according to claim 4 wherein saidcircuit means includes a pulse generator operable in timed relation withsaid relative movement between said body and said type characters forsimultaneously triggering operation of said spark discharge means andsaid third valve.

6. Marking apparatus comprising, a body having an elongated cylinder,means for varying the chamber volume of said cylinder, a movable markingmember received in said cylinder, separate valve and conduit means forseparately and proportionately introducing a plurality of gases intosaid cylinder to form an explosive mixture therein, said mixture whenexploded forming a reaction product which condenses at ambienttemperature, means for heating the cylinder to an operating temperatureabove the boiling point of water to prevent said condensation and formaintaining the cylinder at said operating temperature, a spark deviceextending interiorly of said cylinder, a spaced surface in opposedrelationship to said marking member to permit passage of a record mediumtherebetween, circuit means including a source of power to said sparkdevice for producing an explosion in said cylinder such that theexplosion reaction of the gases 7 8 accelerates the marking member tocause it to mark said 2,883,927 4/1959 Egbert 101-4 record medium, andventing means for removing the re- 3,003,418 10/1961 Young 1014 X actionproduct of the explosion. 3,015,263 1/1962 Lounsberry et a1. 101-19 n3,122,039 2/1964 Sowers 101-3 X Rmrences Cited by the Examiner 53,149,562 9/1964 Wilkins et a1. 101 93 UNITED STATES PATENTS 9/1925Gibson 1O1 4 OTHER REFERENCES 8/1946 Ryan 101-4 X Chemistry ofEngineering Materials; R. B. Leighou; 3/1951 Triplett et a1. 101-4McGraw-Hill Book Co.; 1931, copy Group 470, Class 7/1952 Cook 101 101210 101-DK. 3/1956 Early et a1 101-19 X 10/1957 D l 1 1 1 WILLIAM B.PENN, Primary Examiner.

1. PRINTING APPARATUS COMPRISING, A BODY HAVING AN ELONGATED CAVITY FORCONTAINING AN EXPLOSIVE MIXTURE OF GASES THEREIN, SAID MIXTURE WHENEXPLODED FORMING A REACTION PRODUCT WHICH CONDENSES AT AMBIENTTEMPERATURE, HEATER MEANS RECEIVED IN SAID BODY FOR PREHEATING THE BODYTO PREVENT SAID CONDENSATION, A PISTON MEMBER MOVABLE WITHIN SAIDCAVITY, A MEMBER JUXTAPOSED TO THE FREE END OF SAID PISTON AND INCLOSELY SPACED RELATIONSHIP THEREWITH TO PERMIT A RECORD MEDIUM TO BEINSERTED THEREBETWEEN, SEPARATE VALUE AND CONDUIT MEANS FOR INTRODUCINGAND REGULATING THE FLOW OF SAID GASES INTO SAID CYLINDER IN ACCORDANCEWITH THEIR VISCOSITIES, SPARK MEANS EXTENDING INTO SAID CYLINDER, ANDCIRCUIT MEANS CONNECTED TO SAID HEATER MEANS AND INCLUDING A SOURCE OFPOWER CONNECTED TO SAID SPARK MEANS FOR PRODUCING AN EXPLOSION OF THEGAS IN SAID CAVITY TO THEREBY ACCELERATE THE PISTON WHICH IS CAUSED TOMARK THE RECORD MEDIUM, VENTING MEANS ASSOCIATED WITH SAID CAVITY FORREMOVING SAID REACTION PRODUCT, AND THERMOSTAT MEANS ASSOCIATED WITHSAID BODY AND CONNECTED WITH SAID HEATER MEANS.